Adjustable bushing for drill jigs



Feb. 14, 1950 R. E. MAPLES 2,497,679

ADJUSTABLE BUSHING FOR DRILL JIGS Filed Aug. 25, 1945 I N VEN TOR.

Patented Feb. 14, 1950 UNITED STATES PATENT OFFICE ADJUSTABLE BUSHING FOR DRILL JIGS Richard E. Maples, Lakeville, Mich.

Application August 25, 1945, Serial No. 612,622

. 8 Claims. 1

My invention relates to an adjustable guide bushing for drills, reamers, and so forth, for use in cases where a number of holes in a jig, or in a tool, machine or mechanism may be required to have a center distance or distances from one another or from some point or surface upon the work, all within very close tolerance limits. By the use of my said invention, work of this character may be accomplished without the use of slow and costly jig-boring machines of the wellknown Swiss and similar types.

In carrying my invention into effect the various holes are laid out by ordinary workshop methods, such as by scriber and measuring instruments, and tentatively located with approximate accuracy, and at the centers so located holes are drilled and reamed to properly receive my improved bushings by which adjustments are made to meet very close limits as above stated.

In order that my invention, and the method of carrying it into efiect, may be readily understood I will now describe an example of its use with reference to the accompanying drawings, in which Figure l is a plan view showing a simple form of ji having four holes, with a work-piece held therein.

Figure 2 is an end view of the same.

Figure 3 is a plan view of one of the bushings drawn to an enlarged scale.

Figure 4 is a transverse section of the same showing the arrangement of the component parts of the bushing.

Figure 5 is a plan view of the bushing taken in section on line 5-5 of Figure 4, showing the graduations for adjusting the same, and

Figure 6 is a section of the bushin similar to Figure 4 showing one method of securing the component parts of the bushin in place after final adjustment.

Like characters designate corresponding parts throughout the several views.

In the drawings, A is the body of the jig, hav-'- ing facings Al on two sides and having set screws A2 opposed thereto, whereby the work-piece W may be securely clamped in position. It is assumed that four holes are to be drilled in the work-piece at the points marked H, HI, H2, and H3, and at these points holes are bored in the jig considerably larger than the diameter of the main drill bushings B which they are to receive.

As shown in Figures 3, 4 and 5, the main bushing 3 is surrounded by a pair of auxiliary bushings C and D, arranged one within the other, each of the said bushings having eccentric bores.

In other words, the outer bushing C has its outside diameter a slip fit in the hole in the jig while its inside diameter, eccentric to the outside diameter, is such as to receive the outer diameter of the bushing D with a slip iit. The bushing D is also bored eccentrically to receive the main bushing B with a slip fit.

Thus, when the bushings are assembled as shown, and the eccentricity of the bushings C and D is one sixty-fourth inch in each case, a total variation in the position of the main bushing is obtained amounting to one-sixteenth inch by rotating the bushings C and D through degrees.

To facilitate this adjustment the apices of eccentricity are marked with a dot as at d. Lines are also marked at points 180 degrees therefrom, and the upper face of the bushing D may have graduations G thereon as shown. Notches N are also provided to receive special wrenches for their accurate adjustment.

For example, when the apices are 180 degrees apart the main bushing is central with the hole bored in the jig, and if the apices are each moved through the same number of graduations but in opposite directions the center of the main bushing will be moved along a straight line passing through the original positions of the apices.

When therefore the only necessary correction of the bored holes is to b made along the line a:--a: in Figure 1, that is to say, in the distance between holes H and HI, the apices are originally located upon this line. If, however, there is an equal error along the line y-y, the apices are placed on a line at 4.5 degrees, as indicated at z--z. In both these cases the apices are each moved through the same number of graduations to effect the desired correction. Where the error along the different lines varies, the angle of the line on which the apices are to be originally located may be easily computed as will be understood.

The cases in which measurement of the exact centers by instruments is necessary are extreme ones. For example, where a master work-piece or a template with exactly spaced holes is available all that is necessary is to rotate the eccentric bushings until a plug gauge inserted in the main bushing B will enter a hole in the master workpiece or template.

In Figure 6 of the drawings is shown one method of securing the bushings in place after final adjustment has been made. In this arrangement the main bushing B, having the usual flange BI, is locked againstrotation by the screw S, threadedly engaging the body A, the said screw having an enlarged head SI which enters into an arcuate cavity B2 in the flange. The bushing C has a flange Cl fittin into a counterbore in the body A while the bushing D has a somewhat thinner flange DI fitting into a counterbore in the bushing C, the two flanges being flush with the body as shown.

Now, after the final adjustments have been made, an arcuate counterbore common to: the flange Cl, D! is bored centrally with the screw S and a washer WI is arranged to engage this counterbore and is fixed in place by the shoulder S2 on the screw S, which shoulder is in alignment with the upper surface of the body A.

While my improved method of adjustment has hitherto been described as applied to, a, jig bushing, it will be obvious that the same may be adapted with equal facility and advantage to the bearings of fine machinery and precision instruments.

Having thus described my said invention, what I claim and desire to. secure by Letters Patent of the United States is:

1-. The combination, with a support having a counterbored circular opening and a cylindrical element to be positionedtherein, the b i p ce intermediate said bore and said element, of a pair of eccentric bushings, telescoped one within the other in said, space, said bushings each having flan s, outer surfaces whereof; lie i a common plane substantially flush with a surface of said support, the outer; bushing being a slip fit in said opening and bored eccentrically to receive the inner bushing, and the; inner bushing bored eccentrically to receivesaid element, whereby said element may be accurately located, there being means for locking said bushing-s in adjnsted position relative to said support, said means comprising a, counterbore inthe face of said support, said bushing flanges having. aligned recess forming; extensions of said counter-{bore to provide. a locking recess, a, locking; member fitting in said locking recess, and means. holding, said locking member Within said locking recess.

2. In a fixture, a support, having an aperture therein, a first member having, a portion positioned within said aperture, said first member having an aperture there-in. eccentrically positioned with respect to, the peripheral surface of said portion, a second member having a portion positioned with-in said first member aperture, sa1d first: and said second members being arranged to be rotated relative to each other and to said support, said. members and said support: having, recesses therein which when said members. and sa1d support are in the desired relative positions form a desired pattern, and a locking member sub,- stantially conforming in size, and shape, with sa1d pattern and positioned in. said recesses for holding said first and second members and: saidv support against relative rotation.

3. In a fixture, a support. having an, aperture therein, a first member having a portion positioned within said aperture, said first member having an aperture therein eccentrically positioned with respect. tov the peripheral surface of said: portion, a; second member having a portion positioned within said first, member aperture, said first and said second members being arranged tov be rotated relative to. each other and to said: support, said members and said support havrecesses therein which. when said members .andsaid support are in the desired relative. positions are in alignment, 2.. locking member sub,-

4 stantially conforming in size and shape with said recess and positioned in said aligned recesses for holding said first and second members and said support against relative rotation, and means for holding said locking member in said recesses.

4. In a fixture, a support having an aperture therein, a first member having a portion positioned within said aperture, said first member having an aperture therein eccentrically positioned with respect to, the peripheral surface of said portion, a second member having a portion positioned within said first member aperture, said first and said second members being arranged tobe rotated relative to each other and to said support, said members and said support having recesses therein which when said members and said support are in the desired relative positions align to provide a cylindrical recess, and a cylindrical member of substantially the same size as said aligned recesses and positioned within said cylindrical recess whereby said: members; and saidsupportare held against relativer-otation.

5. In a fixture, a support having, a cylindrical aperture therein a first member having a cylindrical portion, positioned within and substantially fitting said aperture, said first member having a, cylindrical aperture therein, positioned eccentrically with respect to said cylindrical portion, a second, member having a cylindrical portion positioned: within and substantially fitting said first member aperturasaid second; member having, positioning means, located eccentrically to said second member cylindrical portion, said members having recesses which, when said members are in adjusted; positions are aligned, and means carried; by said support and engageable with. both of said members and positioned with in said, aligned recesses for locking both, of said members against rotation relative to each other and tosaid support.

6. In a fixture, a; plate-like supporting member having a cylindrical aperture opening through one face, thereof, saidape-rture havingan; en:- larged diameter portion opening through said a first cylindrical member having a peripheral outwardly extending flange adjacent one end thereof and positioned within said aperture with said flange in said enlarged diameter portion, said; first memberhaving a cylindrical aperture opening through the end, face of;v said first, member adjacent said one end and. having; an enlargeddiameter portion, opening outwardly through said end face, said: first, member aberture being eccentrically arranged relative to the cylindrical: side wall; of said first member; a, 5 ,0.- ond cylindrical member'having aperipheral outwardly extending flange adjacent; one; end portion thereof and positioned within saidifirstmemberaperture with said second member flange; in said second member enlarged diameter portion, said; flanges; and said; supporting member being provided with cutaway portions which, when said members are selectively positioned as desired form a recess of predetermined contour and size, and. means of said, predetermined. contour and size received within said recess for holding said members and said support against relative rotation.

7. In, a fixture, a platelilre supporting member having a cylindrical aperture opening, through one face thereon. said aperture having an err-.-

larecd diameter p r i n openin through said face, a first: cylindrical member havin a, peripheral outwardly extending. flange. adjacent one end thereof: and positioned within said aperture with said flarige in said enlarged diameter portion and an outer surface of said flange coplanar with said face, said first member having a counterbored cylindrical aperture opening through the end face of said first member adjacent said one end, said first member aperture being eccentrically arranged relative to the cylindrical side wall of said first member, a second cylindrical member having a peripheral outwardly extending flange adjacent one end portion thereof and received within the counterbore of said first member aperture, said second member flange having an outer surface coplanar with said face, said supporting member having a second aperture adj acent to but externally of said supporting member aperture, said supporting member second aperture having a counterbore, said flanges having aligned recesses forming extensions of said last-named counterbore to provide a locking recess, and a locking element of substantially the same contour as said locking recess and fitting within said locking recess.

8. In afixture, a platelike supporting member having acylindrical aperture opening through one face thereof, said aperture having an enlarged diameter portion opening through said face, a first cylindrical member having a peripheral outwardly extending flange adjacent one end thereof and positioned within said aperture with said flange in said enlarged diameter portion, said first member having a cylindrical aperture opening through the end face of said first member adjacent said one end and having an enlarged diameter portion opening outwardly through said end face, said first member aperture being eccentrically arranged relative to the cylindrical side wall of said first member, a second cylindrical member having a peripheral outwardly extending fiange adjacent one end portion thereof and positioned within said first mem ber aperture with said second member flange in said second member enlarged diameter portion, said supporting member having a second aperture adjacent to but externally of said supporting member aperture and internally threaded, said supporting member having a counterbore con-- centrically with said member second last-named aperture, said flanges having aligned recesses forming extensions of said counterbore to provide a circular locking recess, and a circular locking member positioned in said loci-ring recess.

RICHARD E. MAPLES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES "American Machinist," pages 565 to 568, Oct. 13, 1927. 

